As is well known, the Positive Temperature Coefficient (PTC) heater is an auxiliary air-heating device. The PTC heater generally has three heat-settings, each is activated by relevant relays. However, the heater is activated, only when the blower operates, from the first step and consecutively to the second and third steps according to the voltage state of the battery.
If the PTC heater operates while the blower is in deactivation, the windless inside of the heater may be overheated, causing a potential fire.
The conventional PTC heater, therefore, should be operated only after the activation of the blower.
Furthermore, the PTC heater takes at least 20 seconds to be heated up after the operation of the blower so that when the user initially activates the heater system, cold air blows into the passenger compartment. If the user turns off the blower in order to prevent the cold air, the PTC heater is also deactivated.
As a result, the quick air-heating type PTC heater is deteriorated in practical use due to the discharge of cold air in the event of its initial operation.